Integrated circuit for diagnostics

ABSTRACT

A fuel cell system includes a membrane electrode assembly, a first plate separator and a second plate separator on opposite sides of the membrane electrode assembly. The first plate separator and the second plate separator have exterior ends away from the membrane electrode assembly. A first gas diffusion layer is located between the first plate separator and the membrane electrode assembly. A second gas diffusion layer is located between the second plate separator and the membrane electrode assembly. The sub-gasket extends from the membrane electrode assembly laterally toward at least one of the exterior ends. A first seal is located between the first plate separator and the sub-gasket. A conductive trace is attached to the sub-gasket and extends on the sub-gasket from an exterior side of the first seal to a location on an interior side of the first seal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to U.S. patent application Ser. No.17/572,679 filed on Jan. 11, 2022, entitled “FUEL CELL STACK AND METHODFOR MANUFACTURE” (Attorney Docket No. 1404.332), the disclosure of whichis incorporated by reference herein.

TECHNICAL FIELD

The present invention relates, generally, to methods and systems formonitoring a fuel cell stack, and more particularly, to systems andmethods for monitoring a fuel cell stack to for variations in electricaloutput and functioning of fuel cells of a fuel cell stack system.

BACKGROUND OF THE INVENTION

Fuel cells electrochemically convert fuels and oxidants to electricityand heat and can be categorized according to the type of electrolyte(e.g., solid oxide, molten carbonate, alkaline, phosphoric acid or solidpolymer) used to accommodate ion transfer during operation. Moreover,fuel cell assemblies can be employed in many (e.g., automotive toaerospace to industrial to residential) environments, for multipleapplications.

A Proton Exchange Membrane (hereinafter “PEM”) fuel cell converts thechemical energy of fuels, such as hydrogen, and oxidants, such as air,directly into electrical energy. The PEM is a sold polymer electrolytethat permits the passage of protons (i.e., H+ ions) from the “anode”side of the fuel cell to the “cathode” side of the fuel cell whilepreventing passage therethrough of reactant fluids (e.g., hydrogen andair gases). The Membrane Electrode Assembly (hereinafter “MEA”) isplaced between two electrically conductive plates, each of which has aflow passage to direct the fuel to the anode side and oxidant to thecathode side of the PEM.

Two or more fuel cells may be connected together to increase the overallpower output of the assembly. Generally, the cells are connected inseries, wherein one side of a plate serves as an anode plate for onecell and the other side of the plate is the cathode plate for theadjacent cell. These are commonly referred to as bipolar plates(hereinafter “BPP”). Alternately, the anode plate of one cell iselectrically connected to the separate cathode plate of an adjacentcell. Commonly these two plates are connected back to back and are oftenbonded together (e.g., bonded by adhesive, weld, or polymer). Thisbonded pair becomes as one, also commonly called a bipolar plate, sinceanode and cathode plates represent the positive and negative poles,electrically. Such a series of connected multiple fuel cells is referredto as a fuel cell stack. The stack typically includes means fordirecting the fuel and the oxidant to the anode and cathode flow fieldchannels, respectively. The stack usually includes a means for directinga coolant fluid to interior channels within the stack to absorb heatgenerated by the exothermic reaction of hydrogen and oxygen within thefuel cells. The stack generally includes means for exhausting the excessfuel and oxidant gases, as well as product water.

The stack also includes an endplate, insulators, membrane electrodeassemblies, gaskets, separator plates, electrical connectors andcollector plates, among other components, that are integrated togetherto form the working stack designed to produce electricity. The differentplates may be abutted against each other and connected to each other tofacilitate the performance of particular functions.

As indicated, a fuel cell stack includes multiple connected fuel cells.Individual cell voltage monitoring is critical for system control anddurability. For example, a cell with low performance can cause numerousfailure mechanisms if undetected. Large stacks of fuel cells maysometimes include hundreds of cells, and cell voltage of such cells iscurrently detected with individual wires where voltage signals aremultiplexed through external circuits. Managing these wires and theirconnections is tedious during an assembly of the multiple fuel cellsinto a fuel cell stack, and there are significant voltage differentialsthat must be managed inside electronics.

Thus, there is a need for improved systems and methods for connectingportions of a fuel cell system to each other.

SUMMARY OF THE INVENTION

The present invention provides, in a first aspect, a fuel cell systemwhich includes a membrane electrode assembly, a first plate separatorand a second plate separator on opposite sides of the membrane electrodeassembly. The first plate separator and the second plate separator haveexterior ends away from the membrane electrode assembly. A first gasdiffusion layer is located between the first plate separator and themembrane electrode assembly. A second gas diffusion layer is locatedbetween the second plate separator and the membrane electrode assembly.The subgasket extends from the membrane electrode assembly laterallytoward at least one of the exterior ends. A first seal is locatedbetween the first plate separator and the subgasket. A conductive traceis attached to the sub-gasket and extends on the sub-gasket from anexterior side of the first seal to a location on an interior side of thefirst seal.

The present invention provides, in a second aspect, a method for use inmanufacturing a fuel cell system which includes attaching a conductivetrace to a sub-gasket. A membrane electrode assembly is located on thesub-gasket such that a lateral portion of the sub-gasket extends awayfrom the membrane electrode assembly toward an exterior of a fuel cellassembly. A first gas diffusion layer is located on a first side of themembrane electrode assembly and a second gas diffusion layer is locatedon a second side of the membrane electrode assembly. The conductivetrace is attached to the subgasket and extends between a seal on thesub-gasket from an interior of the fuel cell assembly past a seal towardan exterior of the fuel cell assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other features and advantages ofthe invention will be readily understood from the following detaileddescription of the preferred embodiments taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a block diagram of a fuel cell system in accordance with theinvention;

FIG. 2 is an exploded schematic view of a portion of a fuel cell of thefuel cell system of FIG. 1 ;

FIG. 3 is an exploded view of a portion of the fuel cell of the systemof FIG. 2 ;

FIG. 4 is a side cross-sectional view of a portion of the fuel cellsystem of FIG. 3 with wires connected to fuel cell plates thereof toprovide connection to other devices;

FIG. 5 is a side cross-sectional view of a portion of the fuel cellsystem of FIG. 3 with metalized traces on a sub-gasket connected to gasdiffusion layers thereof;

FIG. 6 is a side cross-sectional view of a portion of the system of FIG.3 showing a metalized trace on a sub-gasket connected to a gas diffusionlayer;

FIG. 7 is a side cross-sectional view of a portion of a fuel cell systemaccording to FIG. 3 with a metalized trace on a sub-gasket having anupwardly projecting portion;

FIG. 8 is a side cross-sectional view of a portion of a fuel cell systemaccording to FIG. 3 with a metalized trace on a sub-gasket having anupwardly projecting portion;

FIG. 9 is a perspective view of a sub-gasket having a tab and receivinga membrane electrode assembly in accordance with an aspect of thepresent invention;

FIG. 10 is an enlarged perspective view of the tab of FIG. 9 ;

FIG. 11 is a perspective cross-sectional view of a plurality ofsub-gaskets receiving membrane electrode assemblies with the sub-gasketshaving staggered tabs in accordance with an aspect of the presentinvention;

FIG. 12 is an exploded view of the sub-gaskets of FIG. 11 ;

FIG. 13 is a top view of a sub-gasket having a plurality of traces inaccordance with an aspect of the present invention in accordance with anaspect of the present invention;

FIG. 14 is side cross-sectional view of a portion of the fuel cellsystem of FIG. 3 with metalized traces on a sub-gasket connected to gasdiffusion layers thereof and an external monitoring or control device inaccordance with an aspect of the present invention;

FIG. 15 is a top view of a sub-gasket including a thermal couplejunction formed of metal traces in accordance with an aspect of thepresent invention;

FIG. 16 is a side cross-sectional view of a fuel cell system includingthe thermal couple junction of FIG. 15 ; and

FIG. 17 is a side cross-sectional view of a fuel cell system including aplurality of fuel cells having a device connected to multiple fuel cellsthereof for powering the device in accordance with an aspect of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be discussed hereinafter in detail in termsof various exemplary embodiments according to the present invention withreference to the accompanying drawings. In the following detaileddescription, numerous specific details are set forth in order to providea thorough understanding of the present invention. It will be obvious,however, to those skilled in the art that the present invention may bepracticed without these specific details. In other instances, well-knownstructures are not shown in detail in order to avoid unnecessaryobscuring of the present invention.

Thus, all the implementations described below are exemplaryimplementations provided to enable persons skilled in the art to make oruse the embodiments of the disclosure and are not intended to limit thescope of the disclosure, which is defined by the claims. As used herein,the word “exemplary” or “illustrative” means “serving as an example,instance, or illustration.” Any implementation described herein as“exemplary” or “illustrative” is not necessarily to be construed aspreferred or advantageous over other implementations. Moreover, in thepresent description, the terms “upper”, “lower”, “left”, “rear”,“right”, “front”, “vertical”, “horizontal”, and derivatives thereofshall relate to the invention as oriented in FIG. 1 .

Furthermore, there is no intention to be bound by any expressed orimplied theory presented in the preceding technical field, background,brief summary or the following detailed description. It is also to beunderstood that the specific devices and processes illustrated in theattached drawings, and described in the following specification, aresimply exemplary embodiments of the inventive concepts defined in theappended claims. Hence, specific dimensions and other physicalcharacteristics relating to the embodiments disclosed herein are not tobe considered as limiting, unless the claims expressly state otherwise.

In accordance with the principals of the present invention, fuel cellsystems and methods for manufacturing a fuel cell stack are provided. Inan example depicted in FIG. 1 , a fuel cell system 101 is referred to asthe assembled, or complete, system which functionally together with allparts thereof produces electricity and typically includes a fuel cellstack 20 and an energy storage device 30. The fuel cell is supplied witha fuel 13, for example, hydrogen, through a fuel inlet 17. Excess fuel18 may be exhausted from the fuel cell through a purge valve 90 and maybe diluted by a fan 40. In one example, fuel cell stack 20 may have anopen cathode architecture of a PEM fuel cell, and combined oxidant andcoolant, for example, air, may enter through an inlet air filter 10coupled to an inlet 5 of fuel cell stack 20. Excess coolant/oxidant andheat may be exhausted from a fuel cell cathode of fuel cell stack 20through an outlet 11 to fan 40 which may exhaust the coolant/oxidantand/or excess fuel to a waste exhaust 41, such as the ambientatmosphere. The fuel and coolant/oxidant may be supplied by a fuelsupply 7 and an oxidant source 9 (e.g., air), respectively, and othercomponents of a balance of plant, which may include compressors, pumps,valves, fans, electrical connections and sensors. In other examples, theoxidant and coolant described could be separated with a separate liquidcoolant utilized.

FIG. 2 depicts a schematic exploded view of an internal subassembly 100of fuel cell stack 20 of FIG. 1 including a cathodic plate separator 110at an outer end 115 and a plate separator seal 120 on an inner sidethereof. A membrane electrode assembly (MEA) 130 is located between seal120 and a second plate separator seal 150. An anode plate separator 160is on a second end 165 of subassembly 100.

MEA 130 includes a membrane 140 (e.g., an ion conducting membrane)between a cathode side catalyst layer 125 and an anode side catalystlayer 135. A cathode side gas diffusion layer (GDL) 122 is locatedbetween cathode side catalyst layer 125 of the membrane electrodeassembly and plate separator 110. An anode side gas diffusion layer 145is located between anode side catalyst layer 135 of the membraneelectrode assembly and plate separator 160. Seal 120 and seal 150 may bereceived in a channel of on an inner side of plate separator 110 andplate separator 160, respectively. In another example, such seals may beinjection molded around an MEA (e.g., MEA 130) or another fuel cell toprovide a sealing function, such as between an MEA and fuel cell plateseparators.

FIG. 3 depicts a repeating portion 103 of internal subassembly 100 in anexploded view similar to FIG. 2 except that the seals (i.e., seal 120and seal 150) are omitted for clarity, and cathode plate separator 110is omitted. A seal or subgasket 300 is located between cathode sidecatalyst layer 125 and an anode side catalyst layer 135 with MEA 130being received in a cavity 146 of subgasket 300. A gasket or seal 170may be located below plate separator 160.

As indicated, MEA 130 may be received in opening 146 of subgasket 300which may be formed of a nonconductive material, such as a polymer. Asdepicted, MEA 130 may be attached to anode GDL 145 (e.g., via heatsensitive adhesive) and a combined MEA 130-GDL 145 may be sandwichedwith GDL 122 around subgasket 300 such that the components are attachedto each other. For example, the combination may be formed by hotpressing aligned anode and cathode portions (e.g., MEA 130-GDL 145 andGDL 122) to attach such portions to subgasket 300. In an example, heatedplatens may hold the gas diffusion layers (gas diffusion layer 122, gasdiffusion layer 145) and membrane electrode assembly 130 while bonding(e.g., via heat sensitive adhesive or bonding gas diffusion layers tothe MEA) occurs to subgasket 300.

In an example depicted in FIG. 4 , subassembly 100 includes opposingbipolar plates 102 (e.g., plate separator 110 and plate separator 160)each of which may be connected to one of wires 3 for connecting to acontroller or sensor for monitoring and/or controlling purposes, forexample.

In an example depicted in FIG. 5 , metal traces 200 may be connected toGDLs (e.g., GDL 122 and GDL 145) on opposite sides of a membrane (e.g.,membrane 140). As depicted, a first top trace 205 of traces 200 may beattached to, and located on, a first side (e.g., a top side as depicted)301 of subgasket 300 while a second bottom trace 207 may be attached to,and located on, a second side 302 thereof and may extend verticallytherethrough (e.g., through a via) to first side 301. The metal traces(e.g., traces 200) may printed on a subgasket (e.g., subgasket 300)during a metallized printing process or via another method (e.g., vacuummetallization, arc or flame spraying, plating) of depositing a metal orother conductive strip or trace on the gasket. An opening or via may beplaced through subgasket after which a metal or other conductivematerial may be printed or otherwise located in the opening to form ametallized via allowing a bottom trace (e.g., second trace 207) to havean upwardly extending portion 203 extending through a gasket (e.g.,gasket 300)

Traces 200 may include electrical connectors 201 (e.g., formed of aconductive metal or a same material as traces 200) on ends thereofopposite the GDLs (e.g., GDL 122 and GDL 145) to allow an electricalconnection of the traces (e.g., traces 200) and thus the GDLs to one ormore controllers, sensors, or other devices external to subassembly 100.For example, the traces may be connected to a voltage sensor orcomputerized controller.

As described above, traces 200 may connect to the GDLs (e.g., GDL 122and GDL 145) to provide an electrical connection between the GDLs andconnectors 201 to allow an external connection to the GDLs for purposesof monitoring and or controlling subassembly 100 and fuel cell stack 20.For example, subgasket 300 and traces 200 may extend from GDL 122 and/orGDL 145 toward an exterior of subassembly 100. Subgasket 300 and traces200 may extend outwardly past an outermost or exterior end 111 of plateseparator 110 and/or an outermost or exterior end 161 of plate separator160, for example. Connectors 201 could be located to an exterior ofouter end 111 and/or outer end 161 as depicted. The location of theconnectors outside the plate separators and seal 120 and/or seal 150 mayallow additional spacing (due to the exterior location) to facilitate aneasier connection of the connectors to external devices, such as sensorsand controllers.

FIG. 6 depicts a portion of FIG. 5 including portions of top trace 205,plate separator 110, GDL 122, membrane 140, and subgasket 300. Top trace205 extends between subgasket 300 and seal or gasket 120 and is receivedunder GDL 122 and on top of subgasket 300. More specifically, a GDL end206 of top trace 205 opposite connectors 201 contacts, and may beconnected to, GDL 122 to provide a connection between GDL 122 and toptrace 205 thereby providing an electrical connection between GDL 122 anda first connector 202 (FIG. 5 ) of connectors 201. Second trace 207 mayextend between subgasket 300 and seal or gasket 150 and be receivedunder GDL 145 and on top of subgasket 300, as depicted in FIG. 5 , forexample. Further, second trace 207 may extend through subgasket asdescribed above.

In another example, depicted in FIG. 7 , first trace 205 may include avertically extending spike 210 on or near an end 211 thereof to allow afurther penetration of trace 205 into GDL 122 relative to a laterallyextending portion 212 and end 211 of trace 205. Spike 210 may extendinto GDL 122 (but may avoid extending through GDL 122 into plateseparator 110) to provide a better electrical connection (due to alarger surface area and dimensional extent) between trace 205 and thusconnector 202 relative to GDL 122. First trace 205 having spike 210 maybe formed via additional metal or other conductive material beingdeposited (e.g., printed) on trace 205 to form spike 210 duringformation of first trace 205 or in a subsequent step. For example, spike210 may be formed by stamping a metallized plastic forming trace 205.Further, spike 210 may be formed by folding and cutting such metallizedplastic. Second trace 207 (not depicted in FIG. 7 ) may extend betweensubgasket 300 and seal or gasket 150 and be received under GDL 145 andon top of subgasket 300, as depicted in FIG. 5 , for example. Further,second trace 207 may extend through subgasket as described above.

In a further example depicted in FIG. 8 , a trace 208 may be substitutedfor first trace 205, relative to the description above, and an upwardlyextending portion 209 thereof may extend upwardly from a portion 204 oftrace 208 connected to subgasket 300 at a lateral position relative toGDL 122 such that trace 208 does not extend between gasket 120 andsubgasket 300. Upwardly extending portion 209 of trace 208 may be formedvia the methods described for spike 210 and may extend upwardly tocontact plate separator 110. A second trace (not shown) may besubstituted for second trace 207, relative to the description above, andmay be located extend along an opposite side of subgasket 300 verticallyrelative to trace 208 and may similarly extend downwardly to contactplate separator 160. Such second trace could also extend throughsubgasket 300 similar to trace 207.

In an example depicted in FIGS. 9-10 , a subgasket 305 may be connectedto an MEA 330 and a trace 310 may be received on subgasket 130, similarto that described above relative to subgasket 300, MEA 130 and trace205. Further, subgasket 305 may include a projecting tab 340 and trace310 may extend from a GDL 312 similar to GDL 122 and GDL 145 describedabove. Further, a second trace (not shown) may be located on an oppositeside of subgasket 305 similar to trace 207 described above. Connectors350 may be located on subgasket 305 (e.g., tab 340) and connect to thetraces to allow an external device (e.g., a voltage sensor or electroniccontroller) to connect to the traces and thus the GDL's (not shown) onopposite sides of the MEA. Tab 340 may have a longitudinal dimensionextending away from a remainder of gasket 305 and a fuel cell stack(e.g., fuel cell stack 20) sized (along with a transverse dimensionthereof) to allow connectors 350 to be spaced from an outside surface orcasing of a subassembly (e.g., subassembly 100) or a fuel cell stack(e.g., fuel cell stack 20). Such spacing may facilitate the connectionto the device and/or facilitate operation of a device to be connected tothe connectors. Also, tab 340 may have a transverse width dimensionwhich is smaller than the indicated longitudinal dimension which mayallow multiple such tabs to be located adjacent one another in a lateraldirection to facilitate multiple connections to various fuel cells orother components of a fuel cell stack (e.g., fuel cell stack 20).

FIGS. 11-12 depict multiple subgaskets 500 similar to subgasket 305, butwith each subgasket having tabs 510 (similar to tab 340) staggered orlocated laterally to each other along longitudinal dimensions of thegaskets (which may be have edges thereof aligned) and accompanyingsubassembly or fuel cell stack (e.g., fuel cell stack 20). As indicated,the lateral location of the tabs relative to each other may facilitateconnection to multiple devices (e.g., sensor(s) or controller(s)) alonglongitudinal dimensions of the gaskets and may provide space (e.g., dueto a longitudinal extension of the tabs from a remainder of the fuelcell stack and the lateral location of the tabs relative to each other)for connections to such devices and/or provide space between the tabsand devices to allow better functioning of the devices.

FIG. 13 depicts another example of a subgasket 550, similar to thesubgaskets (e.g., subgasket 300, subgasket 305, subgaskets 500) asdescribed above, except that subgasket 550 includes multiple conductivetraces attached thereto via metallized printing or other deposition. Forexample, subgasket 550 may include traces 560 which extend alongsubgasket 550 to various locations to allow an electrical connectionbetween such locations and connectors 570 located on a tab 580 similarto the tabs (e.g., tab 340, tab 510) described above. Further, suchtraces (e.g., traces 560) may lead from tab 580 to sensors or otherdevices located on or adjacent to subgasket 550.

FIG. 14 is identical to FIG. 5 except that a device 600 is connected toconnectors 201 of subassembly 100. In one example, device 600 could be avoltage sensor. The connection of the traces (e.g., trace 205, trace207) to the GDLs (e.g., GDL 122 and GDL 145) may allow such a sensor tomeasure a voltage relative to each side of the membrane (e.g., membrane140) with a circuit thus formed powered by the fuel cell (e.g.,subassembly 100) at 0.6 to 0.9 V when operating properly, for example.Examples of voltage sensors that may be used with the describedsubassembly are described in co-owned US Patent Application No.______(attorney docket no. 1404.333). Device 600 could also be anelectronic controller, temperature sensor or other device for monitoringfuel cell stack (e.g., fuel cell stack 20)

In an example depicted in FIGS. 15-16 , a subgasket 650 may include afirst trace 660 and a second trace 670 formed of dissimilar metal typessuch that differences in temperature would cause changes in electricalpotential thereby creating a thermal coupled junction 680. Morespecifically, second trace 670 may overlay first trace 660 andthermocouple junction 680 such that a change in temperature may besensed through an electrical connection between the first trace andsecond trace. As depicted in FIG. 16 , a seal 690 may electricallyinsulate thermocouple junction 680 from GDL 122. In an example, anincrease or decrease in temperature may be sensed through an electricalconnection between first trace 660 and/or second trace 670 and GDL 122.

As depicted in FIG. 17 , a device 700 may be electrically connected totabs (e.g., tab 340, tab 510, FIGS. 11-12 ) of multiple fuel cells of afuel cell stack (e.g., fuel cell stack 2). Such connection to multiplefuel cells within a stack may provide sufficient power to power adevice, such as device 700, which may be utilized to measure aspects ofthe fuel cell stack, control elements (e.g., motors or other balance ofplant) of the stack or provide other necessary functions. Similarly, adevice, such as device 700, could be utilized to provide measurements ofthe stack being powered by the stack at higher electrical potentials.

In an example not depicted, tabs (e.g., tab 340, tab 510) could haveoutermost edges or lateral edges which may be conductive (e.g.,conductive material, such as metal, may be printed or otherwisedeposited thereon) and connected to traces (e.g., traces 205, 208, 208,310, 560) such as those described above which may connect to interioraspects of a fuel cell stack (e.g., fuel cell stack 20). Such conductivetabs may be vertically aligned to allow electrical connectionstherebetween tabs to allow electrical connection between vertical orlateral portions of a fuel cell stack (e.g., fuel cell stack) tofacilitate the connection of sensors and/or controllers to such variousportions of a stack as described above.

Fuel cell subassembly 100 may be manufactured using a method based onusing a web or plastic sheet which connects components of a fuel cellstack (e.g., fuel cell stack 20) during its manufacture as described inco-owned U.S. patent application Ser. No. 17/572,679 filed Jan. 11,2022. Alternatively, the manufacture of assembly 100 and portionsthereof may be performed manually or a combination of such automated andmanual methods.

Although the above-described examples of conductive traces (e.g., trace200, trace 205, trace 207, trace 208, trace 310, trace 560) refer tosuch traces being printed, deposited or otherwise located on, connectedto, or adjacent, plate separator 110, GDL 122 and membrane 140, themethods of connection of such traces may be utilized with other plateseparators, GDLs and systems described herein. For example, such tracesmay be located on other subgaskets connected to MEAS in multiple fuelcells in a fuel cell stack (e.g., fuel cell stack 20).

While several aspects of the present invention have been described anddepicted herein, alternative aspects may be affected by those skilled inthe art to accomplish the same objectives. Accordingly, it is intendedby the appended claims to cover all such alternative aspects as beingwithin the true spirit and scope of the invention.

1. A fuel cell system comprising: a membrane electrode assembly; a firstplate separator and a second plate separator on opposite sides of saidmembrane electrode assembly, said first plate separator and said secondplate separator having exterior ends away from said membrane electrodeassembly; a first gas diffusion layer between the first plate separatorand the membrane electrode assembly; a second gas diffusion layerbetween the second plate separator and the membrane electrode assembly;a subgasket extending from the membrane electrode assembly laterallytoward at least one of said exterior ends; a first seal located betweenthe first plate separator and the subgasket; a conductive trace attachedto said subgasket and extending on said subgasket from an exterior sideof said first seal to a location on an interior side of said first seal.2. The system of claim 1 wherein said subgasket comprises a first topside adjacent said first seal and said first gas diffusion layer and asecond bottom side adjacent said second gas diffusion layer, saidconductive trace located on said first top side and a second conductivetrace located on said second bottom side.
 3. The system of claim 2wherein said second trace extends through said subgasket to said firstside to allow an electrical connection between said first trace and saidsecond trace and a sensor or controller.
 4. The system of claim 1wherein said subgasket and said trace extend outwardly past said atleast one of said exterior ends.
 5. The system of claim 1 wherein saidtrace extends from said first gas diffusion layer between said firstseal and said subgasket toward said exterior end.
 6. The system of claim1 wherein said conductive trace comprises a first linear portionextending from said exterior side of said first seal toward saidmembrane electrode assembly and said conductive trace further comprisingan upwardly extending portion extending toward said first plateseparator.
 7. The system of claim 1 wherein said subgasket comprises atab extending beyond at least one of said exterior ends in a directionaway from said membrane electrode assembly, said conductive traceextending on said subgasket past at least one of said exterior ends,said tab having a longitudinal axis in a direction away from at leastone of said exterior ends.
 8. The system of claim 7 wherein saidsubgasket further comprises a second trace on a same side of saidsubgasket as said conductive trace.
 9. The system of claim 7 furthercomprising a second subgasket connected to a second membrane electrodeassembly, said subgasket and said second subgasket vertically spacedalong a vertical axis connecting said first plate separator and saidsecond plate separator, said second subgasket comprising a second tab,said second tab located in a lateral direction relative to said firsttab, such that said first tab and said second tab are vertically offsetrelative to each other and non-vertically aligned.
 10. The system ofclaim 1 wherein said conductive trace is a metal trace printed on saidsubgasket.
 11. The system of claim 1 wherein said membrane electrodeassembly, said first gas diffusion layer, said second gas diffusionlayer are bonded to said subgasket.
 12. The system of claim 8 whereinsaid conductive trace and said second trace comprise a thermocouplejunction.
 13. A method for use in manufacturing a fuel cell systemcomprising: attaching a conductive trace to a subgasket; locating amembrane electrode assembly on the subgasket such that a lateral portionof the subgasket extends away from the membrane electrode assemblytoward an exterior of a fuel cell subassembly; locating a first gasdiffusion layer on a first side of the membrane electrode assembly and asecond gas diffusion layer on a second side of the membrane electrodeassembly; the conductive trace extending between a seal and thesubgasket from an interior of the fuel cell subassembly past a sealtoward an exterior of fuel cell subassembly.
 14. The method of claim 13further comprising locating a first plate separator on the first gasdiffusion layer and the seal contacting the first plate separator andthe subgasket.
 15. The method of claim 13 further comprising locating afirst plate separator and a second plate separator on opposite sides ofthe membrane electrode assembly, the first plate separator and thesecond plate separator having exterior ends away from said membraneelectrode assembly, the conductive trace extending from the interiorpast at least one of the exterior ends.
 16. The method of claim 13wherein the attaching the conductive trace to the subgasket comprisesdepositing a conductive material on the subgasket to form the trace. 17.The method of claim 13 wherein the attaching the conductive trace to thesubgasket comprises attaching the conductive trace to a first side ofthe subgasket and further comprising attaching a second trace on asecond opposite side of the subgasket and through the subgasket to thefirst side.
 18. The method of claim 13 wherein said subgasket comprisesa tab extending away from the interior toward the exterior such that alongitudinal axis of the tab extends away from the interior, theconductive trace extending longitudinally on the tab away from theinterior.
 19. The method of claim 13 further comprising locating asecond subgasket connected to a second membrane electrode assembly inthe fuel cell subassembly such that the second subgasket is verticallyspaced along a vertical axis of the subassembly and a second tab of thesecond is located in a lateral direction relative to the first tab, suchthat the first tab and the second tab are vertically offset relative toeach other and non-vertically aligned.
 20. The method of claim 13further comprising locating a second conductive trace on a same side ofsaid subgasket as the conductive trace, the second conductive traceextending from the interior to toward the exterior past the seal.